This invention relates to an improved method of producing an inflatable bag for the protection of a vehicle passenger in a collision of the vehicle.
It is expected that many rapid transit systems as typified by automobiles will be equipped with air bags or inflatable bags in the near future for protecting the passengers against injuries attributable to the so-called "second collision", in a collision of the vehicles. An inflatable bag for this use must have a particular threedimensional shape designed in compliance with the design of the passenger compartment and/or seat of the vehicle when fully inflated, and in many cases the shape is relatively complicated. Accordingly, the inflatable bag is conventionally produced by cutting out a plurality of differently shaped pieces from a sheet material and joining these pieces together by sewing, adhesive bonding or welding. The joining is performed in most cases along variously curved edges of the cut pieces, which are sometimes differently curved from each other. Naturally the work requires skill and long hours, and nevertheless the resulting joints are not always free from wrinkles and exhibit considerably great dispersions in the strength thereof, resulting in that the produced inflatable bag is not fully reliable. From the economical viewpoint, joining of long and variously curved edges inhibits the introduction of highly efficient machines, e.g. sewing machines of the two-needle type, and makes it inevitable to accomplish the work mainly by hand.